no its quite allright!
although they like mum and dad around can they do things independantly? i think your 14 year old is less of a problem. if she palys music you could always make out its too loud and make her wear headphones!
could you tell your son to be out till a cartain time, say somehting like you have an important assignment for work and just to call before coming home?
or could you tell them honestly that you want sdome private time with your partner and that ti dosnet mean you dont want them around, and promise to spend some time with them at a later date